Dusting powder and method of making same



Patented May 10, 1949 DUSTING POWDER AND METHOD OF MAKING SAME James E.Fenn, Baldwin, N. Y.

No Drawing. Application December 9, 1946, Serial No. 715,131

13 Claims. 1

This invention relates generally to dusting powders for use on the humanbody.

It has been known for a long time that the accidental introduction offoreign substances into the human body during surgical operations hasbeen the cause of complications after an otherwise successful operation.One commonly known complication caused. in this Way is the developmentof adhesions within the body after an abdominal operation.

Foreign substances in the form of dusting powder are often introducedinto the human body by the surgeon despite the most elaborate andcareful precautions to prevent this occurrence. This dusting powder isused on the rubber gloves worn by the surgeon in order to enable thegloves to slip easily over his hands. Some of this powder enters thehuman body either directly from the gloves or from the fine powder whichfalls upon the surgical instruments during the dusting procedure. In thelast twenty years, the dusting powder used by the surgeons on theirrubber gloves has been talc. This talc material, known as talcum powder,however, is known to be responsible for most of the aforementionedundesired complications, and the reason for these complicationsattributed to this powder is the fact that talc cannot be absorbed bythe human body. This talc may find its way into any part of the humanbody upon which the operation is performed. Talc, even in the form ofthe finest dusting powder, shows up under the microscope as sharpneedle-like particles interspersed with thin platelets having sharppointed corners. This tal-c has been the cause of suppurating wounds andgranulomas on the tough palms of adults and is much more dangerous onthe tender skins of babies.

The medical literature is replete with reports emphasizing theirritating qualities of talc when injected intr-a-peritoneally,intrapleurally, intrapericardially, or subcutaneously. In fact, in acertain type of heart disease, talc has been recommended to producepericardial adhesions in an attempt to promote better collateralcirculation. Numerous observations and experiments have definitelyproven that talc is responsible for all types of adhesions ranging froma massive type of occulsion of almost the entire peritoneal cavity toless massive localized adhesions of the stomach, spleen, liver andomentum or intestinal loops (folds), or merely thin adhesive bands offixed omental strands that not infrequently cause death from intestinalobstructions, sometimes referred to as strangulation.

The need for a substitute for talc as a dusting powder has been urgentand the search for such a substitute has been long and continuous. Sucha substitute powder must satisfy the following two essentialrequirements: (1) It must possess such a degree of actual or potentialsolubility as to be disposed of rapidly and completely by some form ofperitoneal or tissue absorption, and (2) It must possess such a degreeof insolubility that it can withstand steam sterilization at 15 lbs.pressure without losing that dusting property which serves to preventthe surgical glove surfaces from adhering to one another or to the handsof the surgeon.

As a result of numerous tests made on diiferent powders and manydifferent forms of starch, I have found that although many of thesewithstood the sterilization test successfully, none of them (until thediscovery of the present invention) with the exception of potassiumbitartrate, were absorbed quickly and wihout causing adhesions. Thdifliculty with the starches resides in the fact that duringsterilization they gel. If the gloves were already dusted beforesterilization, the starch forms a hard, stiff coating on the gloveswhich prevents the gloves from slipping easily on the hands. Allstarches, however, were absorbed by the human body without any harmfuleffects. The potassium bitartrate was given to a number of hospitals andused by the surgeons therein successfully, but this particular materialhas these disadvantages: The sterilization process must be conductedvery carefully and the steam pressure not raised above 15 lbs. nor mustthe time of sterilization be prolonged beyond 15 minutes, otherwise thebitartrate will caramelize and lose its dusting properties. It will thusbe seen that the use of potassium bitartrate involves a rather criticalprocedure. Moreover, it was found that the surgical gloves deterioratedmuch more rapidly with the use of potassium bitartrate as a dustingpowder than gloves dusted with talc. Furthermore, potassium bitartrateis not satisfactory for use on the human skin because this chemical maybe toxic and is irritating to the skin on account of its acid nature.

Further history of the attempt to use starch as a dusting powder willnow be given as a background to the present invention. Starch,especially cereal starch (like corn or rice) has granules of very smallsize and would make the ideal dusting powder because the enzymes of thehuman body make the starch soluble and enable the body to absorb it veryquickly. One

of the difiiculties hitherto experienced by research people has been inthe preparation of this n1- terial which will cause it to withstandsterilization in the presence of 15 lbs. pressure of live steam.Attempts have been made, heretofore, to treat starch with formaldehyde,but the resulting product was an insoluble compound. Moreover, suchprior attempts have involved treatment underheat and pressure for longperiods of time, such as 24 hours. It was thought by these earlyexperimenters, that starch treated with formaldehyde could be used forthe sterilization of open wounds because it was believed thatformaldehyde was an antiseptic and the resulting mass would release thisformaldehyde very slowly. However, the treatment outlined above produceda mass which had to be broken up and ground before it could be used forthe purpose desired, and the resulting product was found to beunsatisfactory. The formaldehyde of these previously prepared powdersmight injure the patient;

Other research individuals have treated starch for purposes other thanfor obtaining a dusting powder. For example, Messrs. Rowland and Bauerhave treated starch for paper making purposes either in a watersuspension or dry with a formaldehyde solution and a small amount ofacetic acid in an attempt to produce a starch which will dissolve in adilute alkaline solution and willbe precipitated when the pH of thesolution is lowered. This treatment, however, did not produce a starchwhich could withstand sterilization at 15 lbs.

It was-also proposed to treat starch by suspendingit in water andtreating it with hexamethylenetetramine which is formed instantaneouslywhen formaldehyde solution and an ammonium salt are brought together inwater, to facilitate the manufacture of glucose with this starch. Hereagain, the resulting product will not withstand a pressure of 15 lbs.live steam without gelatinization. This treatment produces astarch whichwill not dissolve in an alkaline solution while the treatment of Rowlandand Bauer produces a starch which will not dissolve in an acid solution.

The present invention provides a dusting powderwhich overcomes all ofthe foregoing difficulties. and disadvantages or prior dusting powdersand which is pure enough to be used in surgical operations, insolubleenough to withstand sterilization, and will be absorbed by body fluidsvery rapidly and without harmful efifects on the human body.

Briefly, I treat starch with formaldehyde in a special manner outlinedin detail below, and obtain a resulting product in fine powder formwhich can be sterilized and is not deleterious or harmful to the tissuesof the human body. Whatever formaldehyde is present in the starchparticles of the powder of the invention is bound within. the molecule,and no free formaldehyde can be detected by the most sensitive presentlyknown chemical tests. Hence, the formaldehyde cannot injure the tissuesof the human body when the powder is accidently introduced within thebody. The process of producing the powder of the invention has theadditional important advantage of requiring only a relatively short timefor.its manufacture and of avoiding critical procedural steps. Hence, itcan be produced commerciallyboth quickly and economically.

Another advantage of my dusting powder is that. it is. nonirritating tothe human skin be- 4 cause it lacks the highly acid nature of thepotassium bitartrate.

The method of producing the dusting powder of the invention will noW begiven: One thousand pounds (1000 lbs.) of commercial corn starch (whichhas a moisture content of about 6%) are put into a dry mixer or anyother suitable equipment. Then equal amounts of water and hydrochloricacid or any other suitable volatile acid (for example, nitric acid) aresprayed into the starch until it satisfies the following test: 25 gramsof starch are suspended in 50 milliliters of distilled water and the pHof the suspension is measured with an electrometric potentiometer. Theacid is sprayed into the starch until the suspension reaches a pI-I of2.2 to 1.8, preferably 2.0. The water prevents the starch particles frombeing strongly attacked by the acid. After this pH point has beenreached, the starch is placed into a vessel which is jacketed so thatsteam can be introduced into the jacket, or any other container whereheat can be applied to the starch inside the container without havingthe steam or heated gas contacting the starch. The vessel is equippedwith an agitator which keeps the starch tumbling So that heatingproceeds uniformly. There is added to the starch in the vessel 15 to 25lbs., preferably 20 lbs., of paraformaldehyde (dry) before the heat isapplied; This formaldehyde amounts to about 2% of the starch. The vesselis then covered and the heat applied corresponding to about lbs. ofsteampressure in the jacket. Within 90 to minutes the starch absorbsenough of the formaldehyde gas generated by the paraformaldehyde towith! stand boiling for 15 minutes in water and the process is finished.During the heating process, samples of the starch are removed and testsmade to determine whether it will withstand the boiling for 15 minutesin water without swelling or gelling. When the starch satisfies thisrequirement, I know that the process is complete. The starch iswithdrawn from the vessel and washed repeatedly with hot water at atemperature between to F. until all odor of formaldehyde disappears. Ihestarch is then washed with a luke warm solution of 1% hydrogen peroxideat a temperature between 110 and 120 F, The hydrogen peroxideinstantaneously forms formic acid with the remaining minute quantity offormaldehyde and is washed out of the starch with another rinsing of hotwater. These washing operations can be carried out in a tank, on acentrifuge or a filter, like the Oliver filters or any other suitableapparatus. After this, the starch is dried in any of the conventionaldriers like the tunnel or the tray-drier, and screened through theconventional dry-starch screens, after which it can be packed ready foruse.

Instead of or in addition to the washing with hydrogen peroxide, thestarch can be washed with sodium .bisulfite in hot water which forms.sodium sulfoxylate with the formaldehyde, and this sodium sulfoxylatecan be washed out readily from the starch. I prefer the washing withwater and. hydrogen peroxide only because I believe that there isobtained a purer product. Tins washing: with hydrogen peroxide inaddition to the hot water removes the last traces of unbound formaldeehyde and makes the product usable asv av dusting powder for surgicalgloves.

Although the procedure mentioned above describes the use of 1900 lbs. ofcommercial-pom: starch, it will be understood that a lesser or largeramount can be used and the-same proev cedural steps carried out, in theevent a difierent amount of the resulting product is desired. If anamount of starch smaller than 1000 lbs. is used, the heating intervalwill be correspondingly shorter, while if a quantity larger than 1000lbs. is used, the required heating interval will be longer than the 90to 120 minutes previously specified. Moreover, the range of pH values of2.2 to 1.8 (preferably 2.0) has been mentioned in order to minimize thelength of time necessary to obtain the resultant final product of theinvention. The method of the invention, however, is not limited to thispH range, since other values of pH can be used, for example, a pH of 3or 4, but this will require a longer time for the heat treatment toobtain the same result. The lower the pH value, the greater will be thedanger of the starch being unduly attacked by the heat treatment. Also,other heating temperatures can be employed with the understanding that alower temperature will prolong the treatment while a higher temperaturewill increase the danger of burning the starch.

Moreover, the temperature of the water used in the washing process mayvary anywhere from tap water temperature to boiling, it being understoodthat the hotter the water the easier it is to remove the freeformaldehyde and the fewer washings are necessary. Any higherpercentages of formaldehyde than the approximately 2% can also be usedin the practice of the invention.

The dusting powder of the invention is not only useful on the gloves ofsurgeons, but can also be used as a dusting powder for bedriddenpatients and babies and as a face powder. It does not cause localizedinflammation (as talcum powder often does), can be dyed with harmlessdyes, and absorbs and holds perfume much better than talc and provides amuch smoother, finer face or dusting powder than presently used dustingpowders.

The process of the present invention functions most efficiently withstarch having as little moisture content as it is commerciallypracticable, because higher percentages of moisture will undoubtedlyprolong the time of conversion of the starch which can gelatinize inwater (and with which I start out) to the desired starch of theinvention which will not gelatinize in water and which is the endproduct of the invention.

The term dry in the appended claims is used in the sense well known tothose versed in the starch industry as designating a starch having lessthan the 25% moisture as contrasted to the wet starch having anappreciably larger percentage of moisture by virtue of being suspendedin water.

I claim:

1. The method of treating starch which includes the steps of acidifyingdry starch with a volatile acid admixed with a minimum amount of waterwhich will give a pH in a range of approximately 1.8 to 4, introducingformaldehyde into the acidified dry starch in such concentration as toprevent gelatinization of starch granules, applying heat and continuousagitation until a sample withdrawn from said acidified-heated starchwill Withstand boiling in water for at least 15 minutes without swellingor gelling, and removing the last traces of free formaldehyde.

2. The method of treating starch which includes the steps of acidifyingdry starch with a volatile acid admixed with a minimum amount of waterwhich will give a pH in a range of approximately 1.8 to 4, introducingformaldehyde into the acidified dry starch in such concentration as toprevent gelatinization of starch granules, then applying heat andcontinuous agitation until a sample withdrawn from said acidified-heatedstarch will Withstand boiling in water for at least 15 minutes withoutswelling or gelling, then washing the resultant product until the lasttraces of free formaldehyde are removed.

3. The method of treating starch which includes the steps of acidifyingdry starch with a volatile acid admixed with a minimum amount of waterwhich will give a pH in range of approximately 1.8 to 4, introducingformaldehyde into the acidified dry starch in such concentration as toprevent g-elatinization of starch granules, then applying heat andcontinuous agitation until a sample withdrawn from said acidified-heatedstarch will withstand boiling in water for at least 15 minutes Withoutswelling or gelling, then washing the resultant product first with waterand then with a dilute solution of hydrogen peroxide and again washingwith water to remove the products of hydrogen peroxide and formaldehyde.

4. The method of treating starch which includes the steps of acidifyingdry starch with a volatile acid admixed with a minimum amount of waterwhich will give a pH of approximately 2.0, introducing into theacidified dry starch paraformaldehyde, and applying heat and continuousagitation until a sample withdrawn from said heat treated acidifiedstarch will withstand boiling in water for at least 15 minutes withoutswelling or gelling, then removing the last traces of free formaldehyde.

5. The method of treating starch which includes the steps of acidifyingdry starch with a volatile acid admixed with a minimum amount of waterwhich will give a pH of approximately 2.0, introducing into theacidified dry starch paraformaldehyde, and applying heat and continuousagitation until a sample withdrawn from said heat treated acidifiedstarch will withstand boiling in water for at least 15 minutes withoutswelling or gelling, then washing it first with hot water and then witha dilute solution of hydrogen peroxide and finally again with water toremove the products of the hydrogen peroxide and formaldehyde.

6. The method of treating starch which includes the steps of acidifyingdry starch with a volatile acid admixed with a minimum amount of waterwhich will give a pH in a range of approximately 1.8 to 4, introducingformaldehyde into the acidified dry starch in such concentration as toprevent gelatinization of starch granules, then applying heat andcontinuous agitation until a sample withdrawn from said heat treatedacidified starch will withstand boiling in water for at least 15 minuteswithout swelling or gelling; removing the last traces of freeformaldehyde, then drying and screening the resultant product.

'7. A dusting powder comprising a starch which is in fine powder-likeparticles and non-irritating when used on the human skin, said starchbeing capable of being absorbed by the human body without harmfuleffects and without causing irritation to the tissues when introducedtherein, said starch being characterized by non-swelling and non-gellingproperties under pressure of 15 lbs. live steam applied for 15 minutes,said starch being produced by the steps of first being acidified whiledry with a volatile acid admixed with a minimum amount of water whichwill give a pH in a range of the order of 1.8 to 4, then treated withformaldehyde in such concentration as to prevent gelatinization ofstarch granules, then heated while being continuously agitated, andfinally treated to remove the last traces of formaldehyde.

8. The method of treating starch which includes the steps of acidifyingdry starch with a volatile acid admixed. with a minimum amount of waterwhich will give a pH of approximately 2.0, introducing into theacidified dry starch paraformaldehyde, and applying heat until a samplewithdrawn from said heat and continuous agitation treated acidifiedstarch will withstand boiling. in water for at least 15 minutes withoutswelling or gelling, then washing it first with hot Water and then witha dilute solution of sodium bisulfite, and finally again with water toremove the products of the sodium bisulfite and formaldehyde.

9. The method of treating starch which includes the steps of acidifyingdry starch with a volatile acid admixed with a minimum amount of waterwhich will give a pH of approximately 2.0, agitating the acidified drystarch, introducing paraformaldehyde of approximately 2% based on theweight of the starch, applying heat corresponding to approximately 100lbs. of steam pressure to the jacket of the vessel containing theacidified-formaldehyde treated starch while continuing the agitationuntil a sample withdrawn will withstand boiling in water for at least 15minutes without swelling or gelling, then removing the last traces offree formaldehyde.

10. The method of treating starch which in eludes the steps ofacidifying dry starch with a volatile acid admixed with a minimum amountof water which will give a pH of approximately 2.0, agitating theacidified dry starch, introducing formaldehyde of approximately 2% basedon the weight of the starch in such concentration as to preventgelatinization of starch granules, applying heat and continuing theagitation until a sample withdrawn from the acidified-formaldehydetreat-ed starch will withstand boiling in water for at least 15 minuteswithout swelling or gelling, and then removing the last traces of freeformaldehyde.

11. A dusting powder comprising starch produced by the steps ofacidifying dry starch with a volatile acid admixed with a minimum amountof water which will give a pH in the range of approximately 1.8 to 4.0,introducing formaldehyde into the acidified dry starch in suchconcentration as to prevent gelatinization of starch granules, applyingheat and continuous agitation until a, sample withdrawn from saidacidifiedheated starch will withstand boiling in water for at least 15minutes without swelling or gelling, and removing the last traces offree formaldehyde.

1.2. A dusting powder comprising starch produced by the steps ofacidifying dry starch with a volatile acid admixed with a minimum amountof Water which will give a pH of approximately 2.0, introducing into theacidified dry starch aldehyde of approximately 2% based on the weight ofthe starch and in such concentration as to prevent gelatinization ofstarch granules, and applying heat and continuous agitation until asample withdrawn from said heat treated acidified starch will withstandboiling in water for at least 15 minutes without swelling or gelling,then removing the last traces of free formaldehyde.

13. A dusting powder made from starch and characterized by non-swellingand non-gelling erties being capable of absorption by the human bodywithout harmful efiects and without causing irritation to the tissueswhen introduc d therein and produced by the steps of acidify y starchwith a volatile acid admixed with a liinium amount of water which willgive a pH in a range of the general order of 1.8 to 1, treating theacidified dry starch with a small per centage of formaldehyde in suchconcentration as to prevent the gelatinizatien of starch granules,heating and agitating the acidified-formaldehyde treated dry starchuntil it will withstand boiling for ,least 15 inonutes without swellingor gelling, removing the last traces of free formaldehyde, then dryingand screening the resultant product.

JAMES E. FENN.

REFERENCES CETED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,507,624 Pollak Sept. 9, 19242,113,034 Rowland Apr. 5, 1938 2,246,635 Moller June 24, 1941 2,397,018Kioeger Mar. 19, 1946 2.417511 Pierson Mar. 18, 1947 2,438,855 Kerr eta1 Mar. 30, 19- 18

